Kennel Club Research Articles

Dimensional and Hierarchical Assessment of American Kennel Club Breeds and Behavioral Trait Descriptions

The AKC functions as the largest and most influential dog breed registry and breed standard information source in the United States. AKC breed standards describe the breed’s overall appearance and behavior. Despite their popularity, the AKC behavioral descriptions and the traits used to quantify them have largely remained unexplored. In this study, we used eleven behavioral breed standard traits for 286 breeds collected for the official AKC source. Dog size and appearance were also evaluated. We employed pairwise correlation and factor analysis to define behavioral trait constructs and hierarchical clustering methods to evaluate the similarity of breed profiles. These methods revealed that although AKC data exhibit various individual correlations concurrent with known canine behavior, many breeds present behavioral trait constructs that do not align with the narratives presented in their standard and may be lacking crucial factors in dog behavior, as suggested by breed group clustering. Our dimensional analysis revealed three constructs, which we labeled as “Social Engagement”, “Pet Demands”, and “Vigilance”, that are very important and relevant to pet ownership. These results emphasize the importance of standardized observations when quantifying behavior and provide an overarching context regarding the strengths and weaknesses of these descriptions, allowing readers to better understand and predict their pet’s behavior.

Evaluation of brachycephalic obstructive airway syndrome breeding test results in Finland from 2017 to 2022

BackgroundBrachycephalic obstructive airway syndrome (BOAS), observed in many flat-faced dog breeds, is one of the most urgent welfare problems in pedigree dogs. Various breeding schemes against BOAS have been implemented in many countries during recent years, but their impact on breed health remains unknown. The BOAS breeding test, used by the Finnish Kennel Club (FKC), includes an exercise component with a recovery assessment, BOAS grading by a veterinarian that evaluates upper respiratory signs before and after exercise, and a nostril stenosis assessment. The aim of our study was to evaluate BOAS breeding test results and estimate the heritability of the BOAS grade using parent–offspring regression from FKC data collected during 2017–2022.ResultsThe majority (80%) of dogs (n = 957) participating in FKC BOAS testing were English Bulldogs, French Bulldogs, and Pugs. In 2022, 89–100% of the litters from these three breeds registered with the FKC had at least one parent tested for BOAS. The proportion of dogs failing the exercise test was highest in English Bulldogs (11%), followed by French Bulldogs (4%) and Pugs (3%). In these three breeds, moderate to severe BOAS signs were reported in 28%, 22% and 30% of dogs, respectively. The proportion of moderate to severe nostril stenosis was highest (71%) in Pugs, followed by French Bulldogs (55%), and English Bulldogs (40%). Estimates of heritability for BOAS grade were separately calculated for these three breeds and for all dogs, and the estimates were moderate to high, ranging from 0.39 to 0.58.ConclusionsThe exercise test alone did not sufficiently identify dogs with moderate to severe BOAS signs. To better consider the complex nature of BOAS and breed differences, exercise tolerance, the severity of upper respiratory signs (BOAS grade) and nostril stenosis should all be assessed together in breeding animals. The heritability estimates for veterinary-assessed BOAS grade indicated that BOAS grade could be used in selective breeding to obtain less-affected offspring.

A retrospective study on whelping seasonality of the Cirneco dell’Etna dog in Sicily, Italy

ABSTRACT Previous to this study, there is no data relating to the reproductive physiology of the Cirneco dell’Etna breed. The birth date of 141 bitches and 104 sires registered at the National Agency of the Italian Kennel Club (ENCI) from all Sicilian breeders, and data related their fertile matings, which produced 266 whelps over a 14-year period, (2009–2022) were collected. Total whelping produced 1069 pups. The mean bitch age at first whelping was 39.13 ± 21.7 months and the mean litter size was 3.84 ± 2.08. The birth period of the bitches and sires was significantly influenced by the month of the year (p < 0.01), as was the distribution of the first (p < 0.05) and subsequent whelping periods (p < 0.01). Whelping distributions show a significant difference between the highest peak in April (which roughly corresponds to a period of heat in February) and in July (which roughly corresponds to a period of heat in May) and the lowest peak in March. No influence of month on litter size and sex ratio was found. Available data suggests that some ancient breeds such as the Cirneco dell’Etna may show seasonal patterns as a vestige of the stricter seasonality of its closest relative the wolf.

Prioritization of Appearance over Health and Temperament Is Detrimental to the Welfare of Purebred Dogs and Cats.

Fashions in the appearance of purebred dogs and cats are encouraged by celebrity culture, social media, and online impulse buying. The popularity of characteristics perceived as cute, quirky, and anthropomorphic has driven increasingly exaggerated breed features appealing to aesthetics rather than health. 'Hypertypes' of some breeds have emerged that take a breed's distinctive appearance to extremes beyond the intended interpretation of breed standards. This has severe, direct and indirect health and welfare consequences. Extreme conformations are associated with chronic health conditions including brachycephalic obstructive airway disorder, ocular, dental, skin, and musculoskeletal disorders. Puppy and kitten farms and illegal traders that meet the demand for hypertypes are associated with poor husbandry that neglects the physical, behavioral, and mental health of parents and offspring. A multidimensional approach involving collaboration between breeders, geneticists, owners, veterinarians, kennel clubs, cat fanciers' associations, animal charities, the academic and research communities, commercial enterprises, and governments is needed to safeguard breeds and tackle these challenges. There are many ongoing initiatives by national kennel clubs and global partnerships to educate pet owners and support responsible pet ownership and sustainable breeding. The resounding message is that health, temperament, and well-being must be prioritized over appearance.

Ethical Concerns about Fashionable Dog Breeding.

The historical relationship between humans and dogs has involved selective breeding for various purposes, such as hunting, guarding, and service roles. However, over time, there has been a shift in preferences from functionality to aesthetics, which has influenced the diverse sizes, shapes, and coats of dog breeds. This review looks at fashionable dog breeding and questions the ethics of prioritising looks over health and behaviour. It aims to alert potential owners, breeders, and regulators to the importance of considering a dog's overall well-being, not just its appearance, which has resulted in fad breeding, leading to genetic disorders, health issues, and a loss of biodiversity. Ethical concerns arise from breeding brachycephalic breeds with respiratory conditions, inbreeding causing inherited disorders, and overbreeding popular breeds while shelter dogs remain unadopted. Additionally, the impact of cosmetic surgeries on popular dog breeds, as well as the neglect of behavioural traits in favour of physical characteristics and strict breeding practices are also considered. The current breeding model can have a negative impact on the emotional and cognitive well-being of dogs, resulting in issues such as aggression, anxiety, and other behavioural problems that can significantly reduce their overall quality of life. Unregulated breeding practices and the demand for rare breeds can lead to illegal breeding, compromising animal welfare. Prospective owners, veterinarians, kennel clubs, and legislators all need to play a responsible role in protecting animals.

Extended deadline for entering Kennel Club awards.

Extended deadline for entering Kennel Club awards.

Dog Shows and Kennel Clubs in Shanghai: British Sport, Sportsmanship and the Changing Concept of Pets in China, 1887–1937

As in many colonial settings, it was the British who initiated dog shows as a sport at the Shanghai International Settlement in 1887. The main purpose behind this development was to increase the understanding and interest of Shanghai residents in dogs, and to spread scientific and refined methods of dog breeding. In this context, the overall aim was to promote the trade of purebred dogs within China. Through dog shows, some upper-middle class Chinese gradually began to consider dogs as pets rather than livestock, and conspicuous consumption of dog-related products and services was in vogue, accompanied by the emergence of dog restaurants, dog hospitals, and dog schools in Shanghai. The popularity of pet dogs and the rise of the pet economy in modern Shanghai was the result of multiple factors such as the elevated status of dogs in the city, the popularity of British sports represented by dog shows in Shanghai, and the general acceptance of western pet views and values among the Chinese elite. It was also a fusion of Chinese and Western cultural exchanges, and the epitome of Shanghai’s modernization process.

Cinética e cinemática do obstáculo passarela em cães de agilidade de diferentes níveis de experiência

ABSTRACT: The injury rate in agility dogs is relatively high compared to the general population. No study to date has considered the biomechanical effects of the dog walk obstacle in agility trials, highlighting a research need. This study assessed forelimb joint kinematics and peak ground reaction forces (PVF) over a dog walk agility obstacle and correlate with experience. Ten (n = 10) dogs were filmed running across a Kennel Club (KC) standard dog walk for kinematics analysis. Two pressure sensors were secured to the (1) dog walk contact area at exit and (2) ground at the end of the dog walk (landing area) for kinetics analysis. Forelimb joints angles and PVF at the contact zone at the walk exit and landing were analysed. A key finding is that the way a dog will move across the obstacle changes depending on their level of experience, with experienced dogs showing faster obstacle negotiation and increased flexion of the elbow joint compared to inexperienced competitors. Higher speeds over the dog walk also resulted in significantly increased elbow joint flexion. Another important finding is that PVF at landing are higher is dogs that are faster and also in dogs performing running technique in comparison to stopped technique. Overall, dog walk obstacle created more forelimbs joint flexion and similar PVF in comparison with previously studied agility contact obstacles which leads us to conclude that further research is required to ascertain the long term health implications for dogs used in agility trials.

Screen interaction behavior in companion dogs: Results from a dog owner survey

Despite availability of video content marketed for dog (Canis familiaris) entertainment, there is little information on dog behaviors when viewing content, nor describing which content is engaging. The aims of this study were to define demographics of dogs that engage with screens, owner observed behaviors, and perceived content interest. A digital survey was distributed to dog owners (03/2022–03/2023). We collected demographics, home environment, owner-rated behaviors, content interest, and interest in 4 presented videos. We compared the representation of dogs from different purebred dog groups (categorized by job/purpose by the American Kennel Club) with the estimated general purebred dog population. Most respondents (total n=1246) lived in the USA (89%). Median age was 4 years, 54% were purebred, 51% were female. Most (86%, n=1077) stated their dog watched screen content. Excitement behaviors were often described: 78% of dogs approached the screen, 76% vocalized. Many owners played videos for their dogs when left alone. Dogs most frequently engaged with animal content; dogs were the most popular animal. Age and visual status influenced the frequency of perceived interaction; age and breed influenced content interest. Within purebred dogs that were stated to watch content, there was a relative over-representation of “sporting” and “herding”-type breeds. A dog’s age, visual status, and breed type may influence their interest in video content at home. Because many owners reported excitement in their dogs in reaction to screen content, owners may wish to determine whether video content would be suitable for use when their dogs are left alone.

Lumbosacral transitional vertebra in 14 dog breeds in Norway: Occurrence, risk factors and association with hip dysplasia

A lumbosacral transitional vertebra (LTV) is a congenital anomaly of the spine and has been suggested to predispose to canine hip dysplasia (CHD). This retrospective, cross-sectional study investigated the prevalence of LTV and CHD among 14 dog breeds in Norway, the possible associations with risk factors, and whether LTV was a risk factor for the development of hip dysplasia. The results were based on evaluation of ventrodorsal radiographs from the CHD screening program from the Norwegian Kennel Club from February 2014 to January 2022. A total of 13,950 dogs were included in the study. For statistical analysis, CHD grades were reclassified from the official Federation Cynologique Internationale (FCI) grades into three grades: CHD free (CHD=A, B), CHD mild (CHD=C), and CHD severe (CHD=D, E). In the study sample, the overall occurrence of LTV was 18.5%, of which 32.9% were type 1, 45.7% type 2% and 21.4% type 3. The occurrence of LTV varied significantly among the included breeds, ranging from 9.5% to 46.2%. There was no association between sex and LTV. The frequencies of CHD grades were A: 43.1%; B: 31.4%; C: 18.4%; D: 6.0%; E: 1.1%. There was a statistically significant association with mild and severe CHD in dogs with LTV type 2 and LTV type 3 (P< 0.001). In the population studied, the prevalence of LTV was different among breeds. This supports initial data on the heredity of LTV and the diverse occurrence of LTV among breeds. Our results indicate that LTV type 2 and type 3 are associated with mild and severe CHD development. Therefore, this study has potentially identified an additional risk factor for the development of hip dysplasia.

Cranial cruciate ligament disease is perceived to be prevalent and is misunderstood in field trial sport.

Cranial cruciate ligament disease (CCLD) is the most prevalent orthopedic problem in canines, affecting 3% to 5% of dogs, causing stifle instability, mobility dysfunction, and pain. The objective of this study was to evaluate the American Kennel Club field trial community's knowledge of CCLD and estimate its perceived prevalence within this population. 401 field trial participants responded, with 701 field trial canines reported. A survey instrument was emailed to a population of Retriever field trial participants to collect information on perceptions and experience with CCLD and current canine participants. Analyses included descriptive statistics, multiple logistic regression, and χ2 tests (significant at P < .05). The majority of respondents appropriately identified the connection between genetics and CCLD (69%). There was under-recognition (6%) of the degenerative nature of the disease, with 61% inappropriately identifying trauma as the major cause. Respondents also indicated that a CCLD diagnosis in a dog's sibling or offspring affected their breeding decisions less than a diagnosis in their parents, indicating a misunderstanding of genetics. More than half of respondents indicated prior experiences with CCLD. The reported occurrence of CCLD was found to be 12% (72/610) in field trial Labrador Retrievers. There is a lack of knowledge in the field trial community regarding CCLD. This population showed a higher owner-perceived occurrence of CCLD compared to data collected from medical records. Further investigation is warranted to validate the true prevalence of CCLD in field trial Retrievers.

Automatic classification of breeds of dog using convolutional neural network

Dog is a mammal that has been a friend of man for ages, it is naturally a domestic animal with a high level of phenotype differences in behaviour and morphology. Breeding and crossbreeding activities have increased the number of dog breeds globally, thereby resulting in dogs with inter breed similarities and intra breed differences thereby creating a difficulty in their classification. The American Kennel Club (AKC) classified breeds of dog into groups based on characteristic, purpose, behaviuor and uses in order to optimize the potentials in the breeds. However, most people find it difficult to identify and classify the dog breed groups. Existing works did not consider the automatic grouping of dog breeds. Hence, there is need for automatic techniques to classify dog breeds into groups with improved accuracy. This work used the concept of Convolutional Neural Network (CNN) to develop a model that will automatically classify dog breeds into group based on the American Kennel Club standard using the Stanford’s dog dataset. The developed model achieved 92.2% accuracy, 80.0% sensitivity, 95.3% specificity and 93.4% area under curve (AUC). The model’s performance is excellent compared to existing works that used the same dataset. The experimental result was validated with two classic CNN models (ResNet-50 and SqueezeNet) using the same parameters.

Pedigree-based analysis of genetic variability in the Chinese Crested dog population in Poland

The aim of the study was to analyse the level of genetic diversity within the small-sized population of Chinese Crested dogs bred in Poland, considering the common occurrence of hereditary diseases, probably related to the high level of inbreeding. The pedigree data provided by Polish Kennel Club were used to estimate different genealogical parameters in the ancestral (n=1,860) and active population (n=1,313). The mean equivalent number of complete generations known per animal reached 5.97 and 6.75 generations in the ancestral and active populations, respectively. The mean inbreeding coefficient values were 0.083 and 0.049 in the ancestral and in the active population, respectively. The effective number of founders (fe) and ancestors (fa) and the ratio fa/fe were 38, 20, 0.54 and 79, 34, 0.43 in the ancestral and active population, respectively. It should be concluded that the genetic variability of the Chinese Crested dogs in Poland is currently at a satisfactory level. However, high proportion of related male-female pairs may cause future mating problems. The population should be monitored for inbreeding and genetic variation. The breeders should choose reproducers in such a way as not to create large groups of paternal half-siblings in the offspring.

A Retrospective Study of Parvovirus Infection in Dogs in Kathmandu

Canine parvo virus infection (CPVI) is highly infectious disease of dogs causing acute gastrointestinal illness in dog with high morbidity. In Kathmandu valley, knowledge on the epidemiology of diseases of dogs is limited. To determine the prevalence of disease in owned dogs in the Kathmandu valley and its associated risk factors, a retrospective study of data from clinical records of the Mount Everest kennel club (old Baneshwor height) during a one-year period was conducted. Using an Excel line graph and pie chart, the prevalence of canine parvovirus infection was examined according to season, age, and vaccination status. A total of 504 cases were seen in the 735 clinical records reviewed, of which 145 cases—or 11.01 % of all cases—had CPVI-like symptoms. The prevalence of CPVI in dogs sold by Mount Everest Kennel club in the valley was estimated to be 11.01% where high cases were observed during the dry season (peaks at April and December) though it could also reach peak during the rainy season (July-August). High number (55.6%; 45/81) of outbreaks were noted among the age group below 3 months followed by age group 4 to 7 months (33.3%; 27/81) and least number of outbreaks were noted in the age group older than 7 months (11.1%;9/81). High number (55.6%; 45/81) of outbreaks were noted among the age group below 3 months followed by age group 4 to 7 months (33.3%; 27/81) and least number of outbreaks were noted in the age group older than 7 months (11.1%;9/81). Disease incidence was highest in German shepherd (21%; 17/81), Japanese spitz (18.51%; 15/81), Labrador (18.51%; 15/81) and mixed/cross (42%; 34/81). Few Vaccinated dogs (7.4%; 6/81) were also found to be tested positive with CPVI. Our finding showed that temperature, breed susceptibility and vaccination status can be the possible risk factors associated with CPVI infection among dog population in Kathmandu valley suggesting pet owners to regularly follow the vaccination schedule, vaccinate their dogs in a timely manner, and routinely check on the health of their canines. Additionally, owners should be aware of the risks and should keep their dogs away from stray dogs.

Evaluating immunological outcomes associated with histotripsy treatment in canine osteosarcoma: a comparative human oncology model

Abstract Osteosarcoma (OS), the most commonly occurring primary bone tumor in dogs and humans, has deficient treatment options and dismal survival outcomes. Spontaneously occurring OS in dogs shares numerous similarities with humans and has greater prevalence, allowing the dog to serve as an informative comparative oncology model. The objective of this study was to investigate the non-thermal focused ultrasound technique histotripsy as an innovative treatment option for OS. Histotripsy has the potential to both ablate the primary tumor and stimulate an antitumor immune response to mitigate metastatic disease, the leading cause of death in OS. To investigate the immunological outcomes associated with histotripsy and OS, we delivered histotripsy to client-owned canine OS patients (n=29) and utilized an in-vitro model for cross species comparisons between human, dog, and mouse. Histotripsy ablation led to a significantly greater expression of activation markers CD80 and CD62L on circulating monocytes, at 1- and 5-days post histotripsy (DPH), respectively. We observed a significantly greater production of TGFβ in circulating monocytes at 3 DPH compared to baseline. On an independent patient basis, we observed a greater population of CD5 +CD4 +and CD5 +CD8 +cells within the treated region of the tumor compared to untreated region and changes in genetic signature also indicated immune activation. Across species in-vitro we observed macrophage activation (CD80, CD62L, and CD86), and upregulation of genes associated with immune cell chemotaxis and pro-inflammatory response. Our results indicate that histotripsy ablation leads to immune activation and has strong potential to target both primary OS and metastatic disease. NIH (1R21 EB030182-01), Focused Ultrasound Foundation (PLL7GBVK and FUSF-RAP-823R1), and American Kennel Club (Canine Health Foundation No. 02773)

Investigating the immunomodulatory effects of histotripsy ablation for osteosarcoma

Abstract Osteosarcoma (OS) is the most common primary bone cancer in humans and dogs. Canine OS shares many biological similarities with human OS and is a valuable comparative oncology research model. In both species, metastasis remains a major hurdle against improved survival, thus warranting a novel therapeutic approach such as histotripsy, a non-thermal, non-invasive, focused ultrasound ablation modality. Histotripsy can mechanically disintegrate gross tumor and potentially induces an anti-tumor immune response to inhibit metastatic development. The objectiveof this in vitro study was to investigate the immunomodulatory effects of histotripsy ablation of canine OS. We hypothesizedthat histotripsy ablation of OS promotes a pro-inflammatory immune signature in primary monocytes and macrophages. We isolated CD14+ primary monocytes using positive selection immunomagnetic cell separation from peripheral blood mononuclear cells of healthy dogs, and differentiated primary macrophages by culturing primary monocytes with canine GM-CSF for 72 hours. We co-cultured primary monocytes and macrophages with histotripsy-ablated canine D17 OS cells for 24 hours, then characterized their cell surface markers using flow cytometry and performed multiplex supernatant cytokine analysis. We observed upregulation of CD80 and CD62L on primary monocytes and a downregulation of CD206 on macrophages exposed to histotripsy-ablated D17 cells compared to controls, suggesting immune activation. We observed decreased levels of the pro-tumor cytokine, TGF-β, from primary monocytes exposed to histotripsy-ablated D17s compared to controls. Our results indicate that histotripsy ablation of OS can induce a pro-inflammatory immune signature. This work is supported by grants from the American Kennel Club Canine Health Foundation, the Focused Ultrasound Foundation.

Trichophyton mentagrophytes complex: A retrospective study of 64 dogs from the Central United States (1997-2020).

There are limited clinical studies evaluating the Trichophyton mentagrophytes complex, with most reports confined to small case studies. Additionally, the studies are dated and provide limited information on response to newer or currently available therapies. The aim of the study was to determine if there is a breed prevalence, lesion distribution and seasonality associated with the T.mentagrophytes complex for dogs evaluated in the central United States. An additional aim of the study was to evaluate response to therapies because there are minimal data available on clinical response with newer systemic antifungal drugs. A total of 64 canine medical records were evaluated that had a previous diagnosis of T.mentagrophytes complex infection. A retrospective study of medical records to evaluate signalment, time of onset of clinical signs, clinical presentation and therapeutic management. A higher incidence of T.mentagrophytes complex infection was observed in the American Kennel Club (AKC) Sporting group (43%) and Terrier group (20%). A seasonal influence was noted, with the onset of clinical signs being highest in October. Lesions most often affected the muzzle (48%), followed by the head excluding the pinnae (21%). Ketoconazole, itraconazole and terbinafine appeared equivalent as systemic therapeutic options to treat T.mentagrophytes complex infections. This study identified patterns in breeds, seasonality and lesion distribution for the T.mentagrophytes complex in dogs from the central United States. Additionally, the study found several reasonable and reliable treatment options for systemic therapy.

Genomic Analysis of the Endangered Fonni’s Dog Breed: A Comparison of Genomic and Phenotypic Evaluation Scores

The Fonni's dog is an ancient Sardinian breed for livestock and property guarding. In recent years, the number of new registrations to the breeding book has slumped and, thus, this breed risks being lost forever. This work refocuses attention to the Fonni's dog, analysing its genomic makeup and comparing different phenotypical and genetic evaluation scores. Thirty Fonni's dogs were ranked by their general accordance to the breed typicality (typicality score) and to the provisional standard by official judges (judges' score). They were genotyped with a 230K SNP BeadChip and compared with 379 dogs of 24 breeds. Genomically, the Fonni's dogs placed themselves near shepherd dogs and showed a unique genetic signature, which was used to create the genomic score. This score better correlated with typicality (ρ = 0.69, p < 0.0001) than the judges' score (ρ = 0.63, p = 0.0004), which showed little variability among the included dogs. Hair texture or colour were significantly associated in the three scores. The Fonni's dog is confirmed as a well-distinguished breed, despite being selected mainly for its work abilities. The evaluation criteria used during dog expositions can be improved to increase their variability and include elements typical of the breed. The recovery of the Fonni's dog would be possible only with a shared vision between the Italian kennel club and breeders, and the support of regional programs.

Effect of inbreeding on the occurrence of genetic defects in Chinese Crested dogs

The aim of the study was to analyse the impact of inbreeding on the frequency of hereditary diseases and the number of genetically tested dogs. The pedigrees of 100 Chinese Crested dogs from Polish Kennel Club and information about genetic tests for hereditary eye diseases and other veterinary diagnoses were collected. Inbreeding coefficients and relatedness were estimated for all dogs examined. The relationship between the level of inbreeding and genetic testing was analysed with logistic regression. The relationship between the occurrence of eye disease carriers and sex or the level of inbreeding was also tested. A significant relationship (P &lt; 0.01) was found between inbreeding and the number of animals genetically tested for PLL eye disease. The effect of sex or the level of inbreeding on the eye disease carrier status was non-significant (P &gt; 0.05). However, in some inbred animals the status of the eye disease carrier could be connected with inbreeding, although this needs further research. We found that most of the dogs had related parents and genetic defects. We also found that the breeders often used related dogs, which reduced the genetic diversity of the group and caused hereditary diseases. We suggest that Chinese Crested dog breeders be more open about publishing DNA-test results, which is fundamental for the health of the breed.

Online Dog Sale Advertisements Indicate Popularity of Welfare-Compromised Breeds

ABSTRACT Kennel club registrations have been used in a number of studies to estimate ownership levels and fashion trends among dog breeds. They cannot, however, give a complete overview of the contemporary trade in pet dogs, and additionally, may be particularly poor at monitoring trends among some welfare-vulnerable breeds. Here, we compared data from online advertisements for the UK sales of single-breed dogs over an 18-month period, with equivalent data (including for prior and subsequent years) from the UK Kennel Club. Kennel Club registration rates and breed popularity rates online were positively correlated. However, some breeds, including the Jack Russell terrier, Border collie and Chihuahua were considerably over-represented in online advertisements when compared with Kennel Club registrations, indicating a hidden market for certain breeds. In addition, the online dataset provided information on the sale and re-homing of adult dogs, showing high rates of adult homing of the Staffordshire bull terrier, Siberian husky and Rottweiler. We conclude that online pet-sales websites are an important and complementary source of data about the market in, and popularity of, a wide range of dog breeds.